The invention relates to universal joints and, more particularly, to a telescopic triplan universal joint bearing retaining spring.
Telescopic triplan joints have been available to the transportation industry for numerous years. Telescopic triplan universal joints provide the necessary angular and elongation movement required by the joint while at the same time, isolating the sprung mass from externally produced vibrations and vibrations generated by the joint itself.
Prior joint designs called tripods transmit loads through the joint during elongation changes due to the sliding action of the joints internal components. As the conventional tripod joint angle increases, the magnitude of the force caused by this sliding action also increases.
Telescopic triplan joints separate the components which are responsible for the angulation and elongation of the joint. This separation of functions enables the joints to utilize rolling friction instead of sliding friction during elongation movement while the joint is at an angle. Thus, these components significantly reduce the loads transmitted and generated by the joint. Unfortunately, the length of rolling travel available to these telescopic triplan joints is limited by the design of the internal components.
In actual vehicle use, the travel requirement of the vehicle universal joint is beyond the rolling travel capabilities of these joints. The triplan joints have a specific amount of rolling plunge which is sufficient to accommodate the smaller amounts of elongation required by engine vibrations or small suspension movements. However, when these triplan joints reach the end of their rolling travel, any additional travel is taken up by a sliding action. Thus, the triplan joint, during sliding elongation, has the same problems associated with conventional tripod joints.
In an attempt to overcome the problems with sliding elongation, earlier designs of triplan joints provided a positioning mechanism for the internal joint components to insure the proper amount of rolling plunge would be available to the triplan joint. Such devices are illustrated by the following patents.
U.S. Pat. No. 4,490,126 issued to Michael A. Orain on Dec. 25, 1984 illustrates a telescopic triplan universal joint. This patent illustrates a return device which helps to position the needle cages at a predetermined position within their travel. While the return device appears to function satisfactorily, it is complicated, expensive and required additional travel to be incorporated into the joint to accommodate the design.
U.S. Pat. No. 4,592,735 issued to Michael A. Orain on Jun. 3, 1986 also recognizes the need for a positioning device. The patent illustrates a non-positive device which utilized different sized needles relative to their location in the needle cage. While the device appears to function satisfactorily, it requires torque to be applied to the joint.
U.S. Pat. No. 4,619,628 issued to Michael A. Orain on Oct. 28, 1986 also recognizes the need for a positioning device. The patent illustrates a spring between the slide and the needle cage. While the device appears to function satisfactorily, attachment of the spring to the needle cage requires both a complicated and expensive needle cage assembly, and the assembly of the joint itself is not fully simplified by using the subassembly feature of this design.
Accordingly, it is desirous to have a needle cage positioning means which is relatively inexpensive, reliable, and further simplifies the assembly of the joint.